The present invention relates to the field of removing cotton fibers from cotton seed or cotton ginning. More particularly, the invention relates to an apparatus and method for efficiently separating the desired cotton fibers from the cotton seed without nepping or fracturing of the cotton fibers.
In the art of cotton ginning, there are two prominent ginning assemblies that are currently employed, with those ginning assemblies being saw gins and roller gins. The most prevalent ginning method is the saw gin, with the basic concept for the saw gin dating back to Eli Whitney. The saw gin provides an expeditious method for removing the fibers from the seeds, but it suffers from several problems. First, the saw gin generates a significant amount of undesirable fiber breakage. Additionally, xe2x80x9cneppingxe2x80x9d (small knots of entangled fibers) commonly occurs during the ginning of cotton with a saw gin. Moreover, another problem experienced with the saw gin is that machine picked cotton often includes a great deal of fine trash in the seed cotton, and the saw gin further breaks up and mixes this fine trash in the cotton. Consequently, it is difficult to remove this fine trash from the cotton. Furthermore, textile mill spinning processes are becoming more sophisticated, thereby demanding even cleaner cotton with less fiber breakage and nepping.
The second popular ginning apparatus is the roller gin, which is well known to persons having ordinary skill in the art. The roller gin is used in some areas because it breaks fewer fibers, produces fewer neps, and produces less fine trash than the conventional saw gin design. However, the roller gin operates slowly, and it is an expensive solution for ginning cotton. Consequently, it does not satisfactorily solve the problems experienced by the saw gin.
Several additional designs have attempted to address the problems present in these two current gin designs. For example, U.S. Pat. Nos. 4,441,232, 4,934,029, 4,984,334, and 5,003,669 disclose various cotton gin designs (commonly referred to as xe2x80x9ccage ginsxe2x80x9d) that attempt to improve the quality of the cotton fibers treated. These cage ginning concepts employed multiple idler rollers having a diameter of approximately 0.75 inches that were placed around the perimeter of a squirrel cage parallel to the cage axis approximately 0.100 inches apart. A series of rubber covered nip rollers were further mounted inside the cage parallel to the cage axis and were pressed against the interior sides of the idler rollers to firmly grip and spin the idler rollers sequentially as the squirrel cage frame was revolved. The rubber covered nip rollers of this prior art had a very high coefficient of friction against both the cotton fibers and also against the idler roller surfaces as the object of each of these prior art designs was to instantaneously grip and spin the idler rollers at the same surface speed as the nip rollers when the rubber covered nip rollers contacted the idler rollers as the cage revolved. While this apparatus provided an improved cotton fiber quality as compared to the conventional methods for ginning cotton described above, the impact and sudden acceleration of the idler rollers against the rubber covered nip rollers caused undesirable and unacceptable bearing failures of the necessarily small bearings at the ends of the closely spaced idler rollers. Even with the small 0.75 inch diameter cage rollers that caused sever bearing failures the seed were unable to come closer than 0.70 inches from the nip point between the 0.75 inch diameter idler rollers and the rubber covered nip rollers. This prevented the roller cage gin from removing enough of the desirable fibers from the seeds and further made the roller cage concept impractical. Additionally, these prior art cage-type gins employing small idler rollers in the cage had the further limitation that the cage rollers and nip rollers could only have momentary line contact as the cage revolved. There are two substantial disadvantages of this design. First, the very narrow line of contact between the cage and nip rollers provided only limited gripping force, and therefore required greater force to be applied by the nip rollers against the cage rollers further contributing to cage roller bearing failures. Second, the momentary line contact between the nip and cage rollers made it necessary to rotate the cage very slowly to remove a significant amount of fiber even with multiple nip rollers. While these attempts may in theory offer improvements over current ginning methods, they do not provide a practical ginning operation.
What is desired, then, and not found in the prior art, is a cotton gin that is able to gin at competitive capacities while better preserving the quality of the cotton fiber.
An object of the present invention is to provide a cotton ginning apparatus that breaks fewer fibers than conventional ginning methods.
A further object of the present invention is to provide a cotton ginning apparatus that creates fewer neps than conventional cotton gins.
An additional object of the present invention is to provide a cotton ginning apparatus that results in fewer particles of trash, such as pepper trash and fine trash, in the ginned lint than conventional cotton gins.
A further object of the present invention is to provide a cotton ginning apparatus having a significantly higher ginning rate than conventional roller gins and sufficiently high capacity to be competitive with saw gins.
An additional object of the present invention is to provide a cotton ginning apparatus that removes fewer short fibers from the seed than conventional cotton gins.
A yet further object of the present invention is to accomplish the above objectives with apparatus whose benefits outweigh its cost.
The rigid cage cotton gin of the present invention includes, in a preferred embodiment, a cotton lock feeder that delivers seed cotton locks that are to be ginned. A high-speed doffing cylinder is mounted proximate the seed cotton feeder to cast the individualized seed cotton locks into a bonnet housing. The bonnet housing includes a series of adjustable air inlet vents in a covering and sidewall that provide airflow to physically deflect the seed cotton locks downwardly into a revolving cage chamber having spaced-apart, annular support rings or discs. A series of sifting bars are fixedly mounted to the support rings, with the adjacent sifting bars being spaced apart to define a series of slots. As a result, the seed cotton locks are drawn to the outer surface of the sifting bars via the airflow passing through the inlet vents into the rigid cage through the slots.
The present invention additionally includes a fiber-engaging cylinder that is mounted within the rigid cage, with the fiber-engaging cylinder rotating in a second direction opposite the rotation of the rigid cage. The outer perimeter of the fiber-engaging cylinder abuts the interior surfaces of the fixedly mounted sifting bars. The outer surface of fiber-engaging cylinder has a very high coefficient of friction against cotton fibers, but a relatively low coefficient of friction against the inside surfaces of the sifting bars. This low coefficient of friction results from a combination of a special fibrous surface on the fiber-engaging cylinder and the polished inner surfaces of the sifting bars. More specifically, cotton fibers cling vigorously to other fibrous surfaces whereas certain fibrous surfaces have a low coefficient of friction against polished metal surfaces. Such an arrangement allows the fiber-engaging cylinder to draw the desired fiber away from the seed cotton locks.
The present invention additionally includes a blocking cylinder that has a series of fin projections mounted external of the rigid cage proximate the exterior perimeter of the fiber-engaging cylinder. The blocking cylinder rotates in the first direction corresponding to the rigid cage, thus the fins move opposite to the surface of the cage at their point of closest proximity. The position of the blocking cylinder is adjustable with respect to the outside surfaces of the sifting bars. The fin projections of the blocking cylinder engage the seed cotton locks that are projecting above a predetermined distance from the outside surfaces of the sifting bars, especially the seed cotton locks with fibers not firmly clamped between the fiber-engaging cylinder and the inside surfaces of sifting bars. The fin projections thereby engage the loose seed cotton locks at the ginning point to knock them back into the bonnet housing for the seed cotton locks to have another opportunity to engage the slots between the sifting bars prior to reaching the ginning point as the cage rotates.
Additionally, a finned clearer cylinder may be mounted within the rigid cage following the ginning point to aid in discharging seed from the rigid cage. The clearer cylinder includes a series of clearer fins that extend from the perimeter of the finned clearer cylinder. The clearer fins enter the slots of the rigid cage and project radially beyond the narrowest point of the slots to eject foreign objects wedged between adjacent sifting bars. The fins are spaced to successively engage the slots in a gear-like manner. The ginned seed and foreign matter will then fall down onto an inclined surface to be discharged.
These and other objects and advantages of the invention will become apparent from the following detailed description of the preferred embodiment of the invention.